Ascomycetes (Sac fungi) MCQ - Practice Questions & Answers

Quick Facts

Ascomycetes (Sac fungi)

Mycelium is filamentous, septate and branched. Cells can be monokaryotic as well as dikaryotic.
Ascomycetes show unicellular (yeast) as well as multicellular organisms.
Ascomycetes can be saprophytic, parasitic, decomposers etc.
Ascomycetes reproduce asexually by means of conidia formation. These conidia are formed on specialized hyphae called conidiophores.
Sexual reproduction takes place by gametangial contact.
The male sex organ is antheridium and the female is called as Ascogonium.
Male nuclei migrate into female gametangium and form the dikaryotic cell. This dikaryotic cell divide and forms dikaryotic mycelium. These mycelial hyphae are called as ascogenous hyphae.
These form fruiting bodies called as Ascocarps. Ascocarp has asci. The two nuclei of each ascus fuse and form a diploid nucleus. This nucleus undergoes reduction division and forms haploid nuclei. These nuclei accumulate cytoplasm around them and develop into haploid ascospores which on germination develop into monokaryotic mycelium.
The fruiting body of ascomycetes is called ascocarp. It can be of various shapes.
Globose and closed ascocarp is called as Cleistothecium (Penicillium).
Flask shaped ascocarp with an apical opening is called as Perithecium (Aspergillus, Claviceps).
Cup-shaped ascocarp is called as Apothecium (Peziza).

Examples of Ascomycetes:

Saccharomyces cerevisiae- Yeast is economical very important in the brewing industry, baking industry etc.
Aspergillus flavus- It is used to produce aflatoxins.
Penicillium- also called blue-green mould. It was used for obtaining first ever antibiotic penicillin.
Claviceps purpurea- causes ergot of rye and other cereals. It is used to obtain lysergic acid which used for treating uterine haemorrhage after childbirth.
Neurospora- also called pink fungi. It is used for conducting genetics experiments.
Morels (Morchella) and truffles (Tuber) are edible.